There is another idea for Full DXL Round-trip, but it is for both design and data. This idea hopes to take smaller bites of the elephant that is DXL support. Lotus should begin by making design elements 100% round-trippable in the next version of Notes. This would open many doors to developers and ISVs, as well as Lotus dev itself.
I know that some members of management and engineering in Lotus do not believe that any extra effort should be put into DXL, because they believe that it is not being used. I say that this is a "chicken and egg" situation; if DXL was guaranteed to be 100% round-trippable on design elements, you would see a plethora of new development efforts in the community - and that hasn't happened because DXL is broken.
Lotus has released this API to the public, and right now it is broken. It is a supported API, and as such it should be given as high a priority as LotusScript and Java.