Ok i'll answer this as i've just found this forum.
I own a '04 Elise 111s, as far as the car being too small I guess it depends on your build, i'm 5'8'' and slim so I have no problems getting in and getting comfortable. However one of my friends who is 6'5'' fits in fine so unless you are some sort of giant there shouldnt be any problems.
The seats are snug and whilst the dont have much in the way of padding I find them very comfortable, my car has leather so i'm not sure what it is like in a standard Elise as i've never actually sat in one. I'm guessing there isnt much difference though.
If you're worried about "only" having a 4 cylinder engine you should maybe arrange a test drive to get a feel for how well these things shift. As i've said I have the 111s so thats 156bhp and I have the Lotus Sport Stage 2 exhaust and induction kit (~20 bhp). Doesnt sound much but when you consider even with the carpets and leather (I didnt go for air-con) the whole car still weighs 800kg.
Even though this car will give most cars you're likely to see on the road it is still essentially a cornering machine - something that really annoys bikers.
Just a side note about the Lotus Sport equipment.....its loud, sometimes when you're driving for a while maybe too loud and i'm sure the neighbours arent happy when I come home late at night. However for a quick thrash the extra noise adds to the whole experience.
The soft top rolls up and fits into the boot with the 4 support beams but still leaves enough room for 2 fully packed backpacks. I dont have the hard top but there is no-where to store it in the car.
Hope this answers some of your questions.
Regards