Hey guys, thanks for the replies, the two-ring solution sounds really good.

Yes, BCD is 110 mm. My only problem is that here in the UK where I am based at my usual online bike-part-sources there aren't any 5-bolt BCD110 rings available that have more than 36teeth...I think these rings may have been phased out by Shimano a long time ago...if you know of any retailers who would stock a suitable ring please send me a link!

Cheers

Lars