I know of at least one company here in Germany designing a tiny focus assist lamp to fit the hotshoe of the Pentax camera. Their goal is a device with an overall size smaller then the base of most flash units (about as large as two dominoes stacked) that mimics the beam pattern produced by the Pentax flash units.
Sadly, since this really isn't the company's expertise (they're struggling with it), nor their main focus (being done on the side), it may be many months before this device finally reaches the market. Because of that, I hope someone elsewhere is working on a similar device and will have it available much sooner. Or perhaps someone has already made such a device and I just haven't found it. Suggestions anyone?
In the meantime, it might be worthwhile to try the laser pointer tactic described on
this page.
stewart