If you don't have a kettle to boil 10-12 gallon's I would make it a BK.
As for the HLT/MT... I would look into making your own. I used coolers for some years and making my own stuff cost me a fraction of what you will pay in that link. However, it's all in what your time and abilities are worth. I have purchased many items I could have made myself but just didn't have the time to get around to it. You know what I mean, your time is worth something.
And in the long run if you will be going to all keggles, just start looking for one or two more for your HLT and MT.