Mahou Shoujo Lyrical Nanoha A's, Mobile Suit Gundam SEED Recommendations
The Nanoha series is basically gundam in loli form with the awesome battle effect. Mahou Shoujo Lyrical Nanoha A's is the second season in the Nanoha series. The first season- Mahou Shoujo Lyrical Nanoha is describing how Takamachi Nanoha and Fate Testalosa met and the development of their friendship, but of course with awesome battles. Nanoha series is just really awesome about its plot and fighting.
In the impossible situation where Gundam became a magical girl series, it would be extremely similar, if not identical, to Nanoha.
In particular, the relationship between Fate and Nanoha reminds me greatly of the relationship between Athrun and Kira. Also, many of the battles from Nanoha often remind me of battles from Gundam SEED.