5.1 Channel Question.

technically, yes, but you may have some problems later. i did it for a while before i got 5.1. i had a speaker wire running across my lap for a few weeks

some 2.0 speakers are wired in the order: line out-speaker-speaker (as in my case of speaker-wire-across-the lap), as opposed to line out-Y split. because of this, you might have some problems with cable length, especially if you have an L-shaped desk.

also, unless you're gonna use passive (unpowered) speakers, the additional speakers will have their own volume and power controls, which is more of an irritation than a real hinderance, but is still something that might bug you.

finally, 5.1 speaker systems are tonally matched. it might sound wierd mixing and matching speakers.

so unless your 2.1 system is really worth keeping (which it may be), i say it might be a better value to save up for a cheap 5.1 system like the Logitech X-530s ($50 in some places, but believe me, they put out more than $50 worth).

the only exception is with certain Creative speaker systems, which let you upgrade from 5.1 to 7.1 with the addition of speakers. i'm not sure they do the same for 2.1 to 4/5.1

it looks as though it would work. i can't really see why not, as long as you have adequate speaker wire. those studio monitors look awesome, btw.