Pentax makes a variety of off-camera flash brackets, hot shoe adapters, and connection cords, which you can see at the Pentax web store. The most interesting one, though, doesn't appear to be marketed in the US — the CL-10 off-camera shoe clip, which is a flash bracket attached via a ball joint to a large clip strong enough to mount the flash anywhere. Oh, and the just-plain-plastic flash table stand is $22 shipped.
Metz makes a wide selection of diffusers, filters, brackets, mounts, and cables, as does Promaster. Sigma's flash stand is the cheapest at twelve dollars, but I think the best bet is Nikon's AS-19 Speedlight Stand, which is designed to either sit on its own or attach to a tripod or light stand — and which is readily available for under $10. I have one and it works very well. The only potential drawback is that Nikon's locking pin goes in a different place than Pentax's, so the pin stays retracted rather than doing its job. The fit seems snug without it, though.