I'm incredibly new to WordPress programming, and not up for the challenge, but I hope someone is.
WordPress needs a BTC plugin to facilitate orders/sales. It could be something relatively simple, like forms with a cart like calculator. Somebody adds or makes a selection within the widget or plugin, a price or calculation of price is performed and returned. Email is collected, wallet sending ID is collected, and a receipt of order (not of payment) is sent to buyer and seller. Then the buyer sends BTC and seller confirms.
Something like that.
Who wants to do it? I bet if you made it, you could put a tip address up, and if it works well in wordpress people will tip it.