I want to get my Talhoffer's blade engraved or etched. Is there anything I should watch out for or is it possible to take it to any generic trophy maker or engraving business?

Thanks guys!

Well, I'd say either give it to an actual cutler/knife seller as, well, it's their profession, or look into giving it to Manning Imperial or Talerwin Forge or somesuch as I'm sure they'd ablige.
That's just my opinion though.

My concern would lean more towards the craftsman's ability to capture the style of historical etching/engraving rather than being concerned about the technique. As such, I'd want it to go to somebody who has knowledge of historical artwork styling for the period of the sword and perhaps some knowledge of swords in general. A historically-inspired piece can be negatively changed with the wrong style of decoration. It sticks out like a sore thumb.

Based on what I've seen elsewhere, if you have a good image of what you want, and at the correct scale, you could print it to a special medium (inkjet) and use that as a resist for home etching. But, FWIW, I think etching is a late 15th c. or early 16th c. innovation, not common on blades even then. I don't recall the chronological details, but C. Blair mentions it in one of his books. 1500 is probably the approximate cutoff date. For certain, you wouldn't want the later German style etching that leaves the main design in relief. The first etching involved scratching the design in the resist, allowing the acid to cut the steel there. The later style involved painting on the resist, often with the earlier method used for small detail and often with a background of tiny dots created by applying small dabs of resist. You can get some idea of the chronology by thinking of the most commonly etched arms and armour--Morions, cabassets, one-piece breasts, glaives, etc. Think 1550.

If you're going to go with engraving rather than etching (I'm not sure if it's possible to engrave tempered steel), I would highly recommend finding someone who does hand engraving, rather than machine or laser engraving. It visually makes a huge difference, and lasts a lot longer. Finding someone who can do it may be hard though; I know there aren't many hand-engravers in the US. I would guess trying a jeweler or a gun shop who may be able to connect you with one. If you're super desperate there is one in Portland, Maine who is excellent and surprisingly affordable, but that'd be quite a lot of shipping from Australia.