I'm following this thread pretty closely. Just starting with multirotors myself, so I'm probably multiple years from what y'all are doing, but I love the Electrohub tri, and how it flies, so imagine a mini tri would be incredible -- even if it would be a handful for me.
You may be surprised at how quickly these things proliferate
October 2013 all I had was a Syma X1 when I set a $100 budget to build a Knuckle (not counting batteries and TX/RX which I already had.)
That knuckle has gone through several MAJOR revisions and no longer even remotely resembles it's original self...the screws on it are the only original part left
I built 3 250 acro quads - one for a friend, one which was to tide me over while I waited on Twitchitys first frame and was then cannibalized to finish that build so I only have 1 actually still in my "hanger".
I was given an emax FPV 250 to build as a GPS experimentation platform - though due to Naze issues and lack of time to fly with a spotter that project has been going much slower than I had hoped.
My wife and daughter got me a proto-x for fathers day.
And now I've got a Hex and a new frame for the twitchity
These things will multiply like rabbits if given a chance
I actually probably have enough bits laying around I could toss together a beater from bits I've worn out or upgraded from. And while my first quad had a homebrewed FC partly to save money but mostly because KK's were never in stock at the time, Naze was considered experimental and I couldn't decide which MW board was worth buying - but I had an arduino on hand and some wii controllers I could hack up for sensors...now I have a MW Flip Pro and an afro mini looking for homes and enough arduino bits and spare MPU-6050's to toss together a few more FC's if I needed them (It was cheaper to buy bits for more than one and I want to experiment with them on a plane for stabilization at some point...and do an integrated RX/FC one of these days.)
Admittedly a good portion of my fleet was gifted to me - but even on a tight budget spending $40-$60 every other month or so I've collected way more parts than I ever expected to have on hand due to my constant need to experiment.
Once the bug bites...these things really start to proliferate!