The Paterson Orbital Print Processor allows you to process up to four 9x11 sheets at a time. It's a nice little daylight processing system and uses just 150ml of fluid, if I recall.
The downside is the initial cost. It's no longer in production, so these often cost about $100. Luckily, it's a one-time purchase. Make sure that it has the little plugs that hold the sheets in place, as well as the orbital base.
Aside from that, perhaps an inexpensive LCD wristwatch with a timer.