Old Glory's got quite a few spandex-clad figures in their Supersystem range that could be painted as various alt-Earth Spideys pretty easily. Going farther afield, you could probably retask the old GW Necromunda Malcadon Spyrers as some kind of power armor Spidey. Same trick might work with their Eldar Warp Spiders, especially the exarch sculpt with the extra weapon arms.