Prices are not listed on the site as most things we have to quote specifics on as every request seems to be different than the last.
Generally speaking as long as no model modifications are needed your typically looking around $100 for something custom as far as a reskin on a model we have already done. The prices go up from there depending upon model modifications needed to make sure things are correct to prototype and so on.
Custom models that have not been made as of yet are considerably more expensive ( think $1K+...) just given the time that goes into modeling something not on our radar yet.
the SD90MACs are something we will be doing but as with everything else we dont do timelines......so i cant say when they will be released.