I think it would be interesting to fabricate a different attachment system for the rake, one that didn't utilize the forks, and provided for full use of the curl function. A crude backhoe of sorts, just not as versatile or maneuverable.
Spark, the setup as I have it does actually allow for full curl on the FEL - there is not lost mobility and that's one of the best things I learned about this setup when first using it. Maybe I'm not quite following your point and, if not, sorry for the confusion. I know you know a little something about fabricating so it may just be something I don't completely follow you on since I am NOT a fabricator!