Have Frontier's disc sales been this strong?!? If it's true then that's quite impressive (yes the source is 4chan).
Top 5 Best Selling mecha show of the last 10 years (numbers in average of copies per volume of DVD/DVD and BluRay):
1. Gundam Seed(And Destiny) (66,000)
2. Macross Frontier (55,000)
2. Code Geass and R2 (48,000)
3. Gundam 00 and S2 (35,000)
4. Gurren-Lagann (20,000)
5. RahXephon (9,000)