For a Thunderbird, I think I'd look for an outboard that had an
alternator, and carry an AC charger. You won't have much space to
store a portable generator.

You're right about not having much space to store anything ;-) Most
thunderbirds have an outboard well in the stern, so the outboard can popup
out of the water and be stored there. Ive got an outboard bracket on my
stern, so that area of storage which is a reasoanble size is free. I could
pretty easily fit a small generator in there (maybe 1000watts) but Im trying
to keep weight down in the stern if i can.

I'd originally envisioned having a very paired down electrical system; a
single100AH battery, which would run a cabin fluro, nav/anchor lights, a
bilge pump, and a cd player, and occasional use of a laptop. The CD player
only draws 1amp, the bilge pump sees hardly any use and if i go with LED nav
lights i should be able to keep my power consumption down to somewhere
around 20Ah/day.

I was thinking to go with a generator to give me some flexibility to use
power tools when i need to, but now its looking more like i might go with a
30W-40W solar panel and a honda 9.9 4 stroke with an alternator in it.

Shaun