As you say, the best solution appears to be to either route over or under, remain visual and just keep out of the bu**ers. Other than that, I haven't found any panaceas either.
I did once watch a very useful DVD (I think a Richard Collins one) which gave some interesting examples of a stormscope in use. I'll see if I can find it and let you know which one. I've found that sometimes the stormscope does give the well defined storms you see in the examples, and then it can be very useful for strategy planning. Sometimes, though, it lights up like a christmas tree all around you, even when you're flying visually in some quite benign stuff. I think it can get confused by strong storms which lie outside its normal range.
I don't know about the rest of Europe, but I believe the London TMA radars specifically have the weather filtered out as much as they can.
If you're a member, I'd recommend posting this on the PPL/IR site. There are people who post there with lots of practical experience. If you're not a member, I'd thoroughly recommend joining.