I wouldn't wait around for the IRD xovers.
If what you mean by 'simple' biamping is using one amp to power the tweeter side of the crossover, and another the woofer side, I'm afraid with the 6.1 it cannot be done. The speakers have one set of binding posts, leading to the crossover, where the channels are mixed save for a few components.
If what you mean is using two amps to power one speaker, I really don't see the need. the t-amp puts out a clean 7 watts, enough to drive the 6.1's to an uncomfortably loud 100db or so in real terms. Plus it may introduce other issues.
Active is a good idea. Rod Elliot at ESP in Australia makes the P09, a nice board for an active Xover. You will need some soldering skills. The advantage here is that you rip out the 6.1 crossover altogether. Not a bad thing as it doesn;t measure too well. You can also upgrade the drivers to something significantly better -- like the Usher models mentioned here:
http://murphyblaster.com/content.php?f=usher2way.htmlor the Peerless HDS range.
I think these will just slot into the cut outs on the 6.1's.
Make an active xover set at around 2.2khz and there you go.