Zik,
Thanks for the quick response.
Preserving the character is pretty important to me, at least now as someone who doesn't live there/etc. The house is in Chicago and over 100 years old. The current owners have pretty fully embraced the bungalow style, even keeping more modern woodwork to the style. It would be a shame to blow that up just to get an extra bed out of things, so I'd spend a fair bit extra to handle better.
Thanks also for the starter thoughts on the types of issues I should be looking for people to be concerned with. I'll probably follow up with pics of the spaces id be thinking of changing tomorrow or soon after.
There already is a large window on I think both ends of the house, so that's cool.
Tomorrow I hope to learn how wide of a usable room could be had without changing the roof at all. If it is practical, it could be very cool to leave the roof and punch through some skylights as the biggest change (and maybe add some solar?).
If I wind up buying this place, will also have follow up questions about basement options.