For longer shanks - no, I've not much luck finding Dremel brand ones, tho I suspect there's gotta be something available for other rotary tools. There's the Dremel Flex Shaft attachment - but I've found the collet is what gets in the way so it's not much help.
I just had a buddy tack weld (TIG) extensions on a coupla bits (in a V made with angle stock so it's true and straight) so I didn't look around much... defo give a shout if ya know/find an alternative
If none of the above is possible fer folks, there's always the tedious but effective (dundundun) hand tool option lol, but I r lazy and hates that heh
Oh and this is prolly obvious, but be careful with longer bits and drop the speed down accordingly (better for this app anyway). At the speeds a Dremel is capable of, even the slight imbalance cause by using the bit can get... exciting (may be why they're unavailable/hard to find)