What about the Bonds growsuits that have no feet? The stripy ones, not wondersuits? My DS is long too and I find that the Bonds suits (or other brand) with no feet are ok - I can put socks on and pull them up. Because they don't have feet it doesn't seem to matter if they are a bit short in the legs, just get longer socks.

DS was born 8th July and I have just migrated him up into 00... tonight he's actually in a Bonds wondersuit that's a size zero... I feel your pain!