Try the Pussycat Patch. I ordered one for my Emisil and it looked great with a little trimming. Just...ignore the squicky name. Or, you can get theatrical hairpieces. Try for smaller pieces with a lace backing (beard pieces, chest pieces...). You can even make your own if you're crafty.
Here are some links:
The Pussycat Patch:
http://www.pussycatpatch.com/id47.htmlThis is the one I purchased. It really is dark brown, though. The seller tried to convince me it was really black but it wasn't. If I reorder, I'll ask for a custom piece in "true" black. Though I had no problem dying mine at home.
False "Chest" Hair
http://www.alliedtrading.com/shop_beautymoustaches.htmI've purchased this as well...it looked ok, but it's a bit too sparse for my liking. This is just one place that sells it; there are many, many others. It comes in two sizes and various colors.
I asked the folks at RM about adherable products. This was their response:
"Our hand-punched hair is sealed into the core of the attachment tab, and is not removable. There are hair pieces available from various businesses on the internet, however we do not offer those particular products. The only possible damage would be from the adhesive used to secure the hair piece...it may leave residue that is not fully removable and can collect dirt."
Honestly, I'd be more concerned that adhesives like spirit gum, prosaide, etc. won't stick well enough to silicone, as most things that aren't also silicone-based usually don't. Prosaide worked moderately well on my Emisil, but honestly the thing I liked most was that I could remove it with 99% isopropyl alcohol, which doesn't effect silicone at all. So safety kind of won out over stability in choosing that adhesive.