I have a two by four with a axle mount on it and Put the bike in at an angle in the rear, it's tight but works. If I am carrrying gear, I just throw it on top of everything and lock it to the roll cage. No problems so far.
I am running a mix of XT and XTR shifter, with Mavic X 517s on XTR hubs, Chris King 1/8 inch headset shimmed down from 1/4 headtube, Really old school Yeti. Marzocchi bomber on the front, assorted Race Face and Thompson stuff just for BLING.