I've been working on improving SilverStripe's template parsing to allow quoted arguments and to remove the arbitrary call signature constraints it currently imposes. Code fixing these issues is now available as a (draft) patch attached to ticket #3738.
Would some of you be willing to test this patch out, verifying that it doesn't break existing template code?
Also, thoughts about the functionality being implemented and the code implementing it are welcome. It would be nice to have comments from fresh eyes after having looked at this code for so long. :-)