If I recall correctly, there was someone who had worked out a serpentine belt conversion for a B/RB engine without spending stupid amount of money for an aftermarket kit.

The long unsupported run of the twin belts from the A/C compressor on the left to the alternator on the right has me thinking of going down this path. There are no matched pair belts to be found these days and I haven't had any luck finding two belts that will track the same.