For those of you who haven't heard the news yet, A!MG will be ending in only two more chapters (four for us) in the June '14 issue of Afternoon to be released on April 25th.
What does this mean for GMT? Our task won't be done with the final chapter. There are still many "Between 1 and 4" panels that we haven't gotten around to editing. It seems they may be released in a neater format with the limited edition of the final volume in July. I'll wait and see for those.
Beyond that, there are a number of possibilities for future work. Mangas, AMG books, etc. It'll all depend on translator interest.