Uncompressed: 13,1 MB
Compressed: 1,59 MB (Using RAR, Best compression, Solid Archive)
I think you could even make it take up less space on the memcard by using ppf-files going up from the lowest dash to the highest.
To get a 5659.17f14d00 dash from a 4034 dash:
4034 >PPF = 4817
4817 >PPF = 4920.10027100
4920.10027100 >PPF = 4920.1012a700
4920.1012a700 >PPF = 5659.17e4cd00
5659.17e4cd00 >PPF = 5659.17f14d00

Edit:
Something else I have been brainstorming about is the use of AvaNetPrep.
This would eliminate the limited size of the memorycard.
(But obviously would require the user to connect the xbox to a pc and manually edit some settings first (for instance sharing a folder on the pc))