I’d been under the impression you couldn’t use Turbo Type with onscreen keyboards at all. I was mistaken; Turbo Type works, for the most part, with the Hot Virtual Keyboard. (I should really edit my review of HVK now that I can actually use it and it’s been updated since — the demo more or less rocks.) The only thing you can’t do with that combination is accept a word with Space. Enter, Tab, arrows and Enter, and the number keys work fine.
Turbo Type does not, however, work with the Click N Type or the Windows XP/Vista onscreen keyboard. I don’t know about 7. If you want to combine custom layouts and keyboard macros and smart punctuation with decent word completion and expansion, Hot Virtual Keyboard with Turbo Type is probably a good thing to have on your flash drive. Especially if you want to do it cheaply.