I've been spending some spare time trying to get the BUG as a wifi AP. I'd pretty much given up on libertas_tf because it was specific to the Marvell Libertas 8388 USB 802.11b/g cards (as I understand it), and the 88W8388 used in the OLPC XO-1.
Anyway, it looks like the OLPC XO-1.5 will be using the 88W8686 Marvell wifi chipset, which could have some sweet windfall for BUG users. Have a look here:
Looks super promising! If this is a go I'll definitely follow-up here with a how-to. In the meantime, thanks OLPC devs!