Here's a nice EA developed by a contributor to Steve Hopwoods Forex forum called "MultiBob".
It trades an implementation of a manual trading system developed by a guy called "Nanningbob" across many currency pairs simultaneously.
I've been manually trading Nanningbob's 10.2 system for a while on demo charts, and have had a fair amount of success with it. The system uses weekly pivots as support and resistance levels, and the weekly open for the last two weeks as a guide to the trend.
Here's the current results:
Up almost $1,000 on a $5,000 FXDD demo account in two weeks. Not bad.
However, due to a bug, this robot had several AUDNZD trades open at once. The market moved in their favour creating most of the profit. Still, it's not been doing too badly with other trades and it's an interesting design.
It's not possible to run back tests on this sort of robot, so we have forward test results only.
I've been keeping the robot up to date as new releases come out, and use the default settings.
If you're new to Steve Hopwoods forum, beware. It contains a lot of very useful information, but I have noticed the posters can be a little enthusiastic about almost every system that comes out. If you're not careful, you might mistake the site for the holy grail of trading, load all of the offered EA's onto charts, and lose all your money.
Update: Another week of results, and this robot has managed to wipe out all those gains - over $1,000, gone!