You definately don't want to be considering anasthetic for things so simple as nail trimming etc. The risks and such are just totally 100% not worth it. Even if it means trancing the bun (and possibly stressing them a little) then that is definately the way to go imho. The stress and effects of coming out of an anasthetic, let alone the stress of disorientation in a place they don't know with different perhaps scary smells and sights etc., are going to be worse than trancing a bun in your arms in their own home.
Benji will not trance. No way in a million years. I have tried for 4 years, and he just squirms and twists and I worry he will hurt himself in the process. Luckily he is very good when I clip his nails etc. and he behaves himself immaculately with other situations too, like having his teeth trimmed.
Pippin I usually trance when clipping nails. Luckily he is very easy to trance. I lay him on my bent legs, clip clip clip in under 10seconds, then hug him tight to me, treat him with banana and he hops off happily. He doesn't appear to be stressed but there has been some controversy about trancing and whether or not it is a calm state, or a state of tonic immobility in the case of being captured by a predator.
You just need to find a way that works for you, really. With Benji, I have him on my lap, facing away from me, distract him with a crunchy bit of apple etc. and gently move his paws away from his body so I can clip them. He is so used to it now that he is very good. Occasionally I have someone help me, if he's being a littl feisty, but even then it's just someone hugging him and giving him kisses and nose rubs, while I clip quickly.
I have never tried the bunny burrito method, and hopefully won't need to. If a bun is used to being burritoed then it shouldn't be a huge problem for them, but as mine aren't used to it then I wouldn't like to stress them out by starting it when my other methods work well.
You could also try sort of, half trancing him. Get someone to place their hand round his shoulders, place one under his bottom, and hold him up, and close to their chest with him facing away from them. This puts them slightly on their back, so may trance them slightly (this has been from my experience anyway), and then you can clip their paws, which are conveniently facing you and away from their body.
Of course, lots of nose rubs and treats afterwards. The more they can associate nail clippings with yummy treats and good things etc. the more likely they will tolerate it.
Jen