These are some mechwarrior figures I cut off the clix bases and repainted/rebased. I bought quite a few of the MW power armor and picked out the ones that work OK with 15mm. They are a little small, but based up on a "hill" of putty they don't look that out of scale. I don't know any of the MW names for these, as I never played MW, but you should be able to check the wizkidsgames website to find out if you're interested.
These two are actually big enough and look good next 15mm figures.
These are the regular power armor. They are rougly 15-18mm tall each.