Sorry this is long, but I am hoping to get a few good recommendations and any assistance would be greatly welcome!
The background: My hubby and I love paddling and we each have older 14 ft Current Designs sit-ins we will never part with. But after our first kiddo came around we switched to family canoeing trips. He is now 7 and we just got him a youth kayak he is learning very well with. We live in S. Fl and frequent shallow, calm rivers and streams; no extreme ocean swells going on here just the possibility alligators!
Now for the question – We also have a two year old and I would really like a sit on top kayak, for myself, which would accommodate him too. It doesn’t need to go fast, just needs to be stable and most importantly, be something that I (at 5’4) can maneuver easily myself. Years ago Ocean Kayak had a 12 ft Sidekick which was designed for a single adult and a kid…I think that boat became the Scrambler 11 but it no longer has the second seat? I am probably wrong, but I think the the bow rigging in the scrambler could be fitted with a seat in lieu of bungee cords??? But I haven’t seen one in person.
So here is what I dream of and please let me know if you know of something out there that fits the bill or might come somewhat close….
Stable SOT
Possibly less than 50 lbs
Is a solo style but has a child jump seat – or has bow rigging were a seat can be installed – or just a place in front were a kiddo could sit for a bit in comfort……
Is 12ft or less - I don’t want a true “tandem” this is really for me and the occasional child 
I know the peekaboo is out there and I found some good prices (around 500) but I’m not sold on it yet. I could careless about the window, there isn’t rigging for an actual seat and frankly, it is a beast. Not sure if that would matter in the long run and for the price I found it might be the best deal… it is just soooo heavy! Ideally this will last me for many years and is something that once my 2 year old is off paddling by himself I can still use solo and keep up with the family.
And before you ask: yes we are very experience on the water, yes my 2 year old has a well fitted life preserver, yes he is already taking swim classes, and no we don’t plan on being out for extended times or in the open ocean 
Any advice?? And Thank you in advance for sharing any experiences or recommendations!!!
sit in the SOT
there are many tandems out there of varying lengths and widths.
That being said, when the kids were young, I would pop off the front hatch of my perception illusion and put one of them inside the bow compartment. It worked quiet well on a small flat lake.
Funny thing is, I just came across some pictures of this the other day after not having seen them in years.
Not crazy about this yak, but…
Search for the “Lifetime Kokanee Tandem Kayak”. Home Depot sells them online (weird). I am not crazy about the reputation of Lifetime and don’t own one (I do own a cheap SIK, but that’s another story). But look at the layout. It’s ridiculous to have a tandem that small; the front seat is a joke unless it is for a small child. Which is exactly what you want. The yak may be fine; don’t know. But it may help to know such a thing exists for comparison.
Bic
Check out the Bic sport kayaks, they're listed here. They have a range of SOT with 1, 2 and 3 seats. One might be what you're looking for, although I think they're a little heavy.
The Scapa is a nice single, but is long. The Bilbao is a single, and the picture here shows it with a kid in the front, so looks like it's what you want.
FeelFree Juntos
is pretty much exactly what you’re describing – a solo SOT under 12 ft long with a child seat option. it weighs 60 lb (your 50 lb requirement will be hard to meet in a SOT), but it has a built-in wheel, so you won’t have to muscle it around as much.
Just my 2 cents.
We have two OT Loon 111’s that are great for taking along a youngster when we install the kids seat we purchased for grandkids long ago. Only problem (?) we had was that each time they went for a ride, they fell asleep in the seat. we no longer have use for the seat, but it installs easily.
This kayak has an open 55" cockpit, but no hatches so floatation might want to be added if used. We’ve never done so, but it’s an option.
The boat tracks well and is not too heavy. It is our son’s and one of his friends favorite when they paddle the Muskegon River with friends as there’s plenty of room for tackle and bait.
prodigy 13.5
Here is a short video: http://youtu.be/422J0Px2o7I
I just bought a prodigy 13.5 for me and my4 year old to take out in the rivers snd lakes around louisiana. We absolutely love it. It is sturdy, easy to navigate and is light enough for me to load/unload by myself. It can be used as a one man-er too. I only wish it had a frain hole. But other than that, I highly recommend it.
apologies
Sorry for all the misspelled words!