finished a couple drawings of Spike and Rumble that I sketched traditionally and lined/colored digitally. here’s some of my thoughts as to how they met/got together in my AU:
 
Rumble and Spike are at least aware of each other during the show but don’t really interact until both of them are in their teens
 
Both of them begin attending the School of Friendship at some point; Spike goes because Twilight suggests that it would be good for him to further his education, and with her increasing number of Princess duties, it’s harder for her to tutor him herself - and because it would benefit him to have more time socializing with ponies his age. Rumble attends because why not
 
Rumble is also really good at math, so their paths don’t really cross until Rumble reluctantly joins the Mathletes (which the School of Friendship has in this AU) after being very enthusiastically encouraged by his teachers.
 
Spike is the moderator at their first tournament/competition against another school and quickly notices Rumble’s staggering mathematical ability and his seeming nonchalance about it; Rumble isn’t full of himself like some of the other Mathletes seem to be.
 
After the competition, Spike approaches Rumble and they start talking. As they get to know each other better, Rumble finds himself drawn to Spike’s determination and his willingness to work hard, not to mention how smart he is.
 
Currently, they are married and have a son named Hurricane together.
 
in case you don’t know what the Mathletes are, you can read more about them here. in short, it involves students solving as many mathematics problems as possible in teams that are competing against one another. also, this is my design for adult Spike, since I kind of don’t like his final appearance in the show and I always envisioned him as looking more like a Western Dragon.