Forget that we said he's a commercial bootlegger. Let's say I heard some amazing recordings all coming from the same taper and was curious about how to reach that quality. For some reason the taper doesn't want to share his tricks, may I discuss it with the nice and knowledgable people on this board...? This of course is irrelevent if this taper made average recordings like you say...
It sounds to me like you may not have much experience with non-commercial live music, but you do have some experience with these Crystal Cat releases. You think that the Crystal Cat releases sound better than those non-commercial recordings you have heard and would like to be able to achieve this level of sound quality. I believe you are expecting a quick answer on what the best equipment is for recording live music. In essence, this whole board is an answer to exactly that question, and as you may discover by the large amount of information at this (and other similar sites), this is a difficult question to answer.
There is no perfect set of equipment for what you want. Some venues inherently sound like crap and even the most expensive setup won't help you there. But if you are looking for the best recording, I would get a ticket to a venue with good acoustics in the so-called "sweet spot" for that venue. This spot may not necessarily be front row, but it definitely isn't nose bleeds either. You will have to research this yourself. Next you will have to invest in a good quality set of microphones that you can easily sneak into the venue and keep hidden so you won't be ejected. If you want high-end stuff, it will cost you somewhere between $600 and $4000 a pair. You can spend even more, but that is a good range. You will also need equipment to provide power to the microphones, provide gain, convert the signal from analog to digital and something to record that digital signal with. All told you could easily drop $10K or more on a really nice stealth setup. More money doesn't necessarily mean that you will get a great recording though, but coupled with experience, luck and the above golden ticket, you will usually have recordings that some people will really like. It is often helpful to obtain a soundboard patch to mix this recording with an audience recording to produce something that may sound clear but has hints of room ambience as well as crowd noise. If the band doesn't allow audience recording of its concerts, I think you may find a soundboard patch difficult to obtain.
This person (or company) Crystal Cat takes advantage of fans of live recording by passing off the recordings freely circulated as his own and then selling them for profit. This pisses off the musicians and the people who legally profit off them. It also pisses off the people on this site because we spend a good deal of money and time to make these freely available because it is something we enjoy doing and the music industry typically views us in the same light as Crystal Cat and makes it as difficult as possible to do what we love to do.
You are asking what Crystal Cat uses, and the likely answer is that he uses OUR equipment which includes DPA, Schoeps, Neumann, MBHO, Microtech Geffell, AKG, Sony, Tascam, Oade, Grace, Apogee, etc products. How much does all this cost? I guess you would have to ask every taper he has taken advantage of and add it all up.
If you would like a good set of equipment to stealthily record concerts, I would read what different members use, listen to some of their FREE recordings and then buy the equipment you think consistantly makes the best recordings.