Extracting samples from Reason

You'd have to use Rewire to get it to sink up with a sequencer.

Look on version tracker for a utility that will capture audio streams and output them to wav. That would be the easiest immediate solution.

reduce your loop to the size that you need it to be (however long the sound plays for). export the sample hit to a .wav using the file menu. done. roundabout, but as far as i know this is the only way.

right... other than an sequencer sync.

f that, get on Fruity Loops, it is much better to make Grime beats with.

Well, actually, I tried to export a loop of some specific size, but it's not the same.
In fact, Reason somehow recognizes files that are native. When you use internal samples, it can modify it's length and play it for as long as you need. But when you use your own samples (even exported from Reason and imported back as you said), it plays it just for one time.

As for Fruity Loops, I use it, too, but it doesn't fit for some tasks.
I need to pitch samples so that they will have frequencies different from common (so they won't coincide with keyboard frequencies) and then sequence them just like usual tones. It's much more convenient to do that in Reason, because FL goes crazy when there are too much tracks in sequencer. And it doesn't allow to bind samples to piano keys.

Anyway, thank you all for your advises. Maybe they'll give me a push in the necessary direction.

when you're done makeing the music, can YouSendIt to me for my grime blog?

well, I would be glad to send it to you, but I'm not sure I'll manage to make real grime from my experiments =) my music isn't yet enough professional to be unambiguously defined as grime or some other genre.