Fair warning: This was a daft idea - and probably a bit on the difficult side (This puzzle exists to get the idea Out Of My System). My reference basis also means that I had free reign to be... well, let's just say that I wouldn't usually include some of these fill answers! I apologise in particular for 1D.
This is the first puzzle where I've made use of the "Suggest" feature on clues! It certainly made a fair bit of the construction work easier - especially since this grid isn't my cleanest (This is your warning now!), so has a fair few acronyms/"common" crosswordese options where there's limited room to reinvent the wheel. Perhaps I should have been more willing to kill my darlings (Much as I did on my first Themeless, given the numer of drafts that had was... yeah...), or reduce my theme entry count to free up space... but alas! So yes, you have been warned!
Oh, and yes, not adding "Boris can keep his stinking mitts off it" to 36D was painful.
Finally: I have a 13x13 Cryptic Grid in process! Which means "I've done the relatively easy bit - gridding the thing - and I've now got 28 cryptic clues to write up". Hopefully it'll be with y'all soon :D