Has some PD-program comparable to Prominy V-METAL already been written? For a demo of Prominy V-METAL see:

@Nobody The product page says: 10.4 Gb of wav files, so it's not synthesising the sound. If you had the same library of recorded sounds I guess you could play them in Pd, but it would be awkward at best to manage that many samples. As for an emulation of the guitar interface, after much fiddling and pain you could come up with something very, very rudimental, but anything remotely realistic is beyond the capabilities (or scope) of this environment.

Thank you! So if I understand correctly Prominy V-METAL basically contains almost everything a good metal guitarist could do on an electric guitar and just replays those sounds as instructed?

Could it be possible to synthesize the sound of a metal guitar by means of physical modeling (differential equations) with the movement of the plectrum and fingers of the guitarist as input signal?

@Nobody It looks like that's what's going on to me after a quick look at the product page, but I must say I didn't know it existed before seeing this thread.

It is definitely possible to physically model a guitar sound, although that might not get you as close as a sampling approach would. Metal or not, a guitar sound comes from vibrating strings, and to model that you can look into a technique called "Karplus-Strong synthesis". Hope it helps.

Does there already exist a guitar emulation on the basis of Karplus-Strong synthesis in PD-vanilla?

@Nobody Also the PMPD library. I don't know if it's available for 64-bit.
This sort of works (more wooden instrument sound) but for higher pitches and more "metal" sound the string would need to contain many more "masses" and I think the cpu might suffer....... 51_string1~.pd
David.

@Nobody This is the most basic Karplus-Strong emulation of a string. karplus~.pd
For emulating the rest of the instrument you'd need to include other aspects in the model, such as picking position and of course the body resonation as @whale-av mentioned. This might be easier to do for an electric guitar than for an acoustic, but I wouldn't know how to approach either.
Having said that, when you say "metal guitar" I guess you mean the genre like in the video you posted and not a guitar with a metal body like a dobro, if that's the case for emulating a very heavily distorted sound you might get away with a less-than-perfect model, and you can concentrate on modelling the amp, cabinet and effects. After all, the unprocessed sound of an electric guitar is pretty unimpressive to begin with if compared with the final processed sound.

Thanks for the tips and information!