There's nothing that quite matches a personalised name stamp, but it occurred to me that an alternative is to use Engineer's Marking Stamps, which are available in both numbers and letters in quite a range of sizes. Examples would be these from Smith Francis Tools -
http://www.smithfrancistools.co.uk/marking.htm - which can be bought through good engineer's suppliers, and of course budget examples of far eastern manufacture will be available through the likes of Ebay and Amazon. Search for 'letter stamps' and 'number stamps'.
Using them does need a little bit of practice to get a good result, since something like an 'm' will need a bit more tap than an 'i' to give the same depth of impression. Setting them against a straightedge of about 1/2" thickness or so helps to get the impressions neatly aligned.
One advantage is that they'll mark soft steels, brass and wood with equal ease. Don't hit so hard when marking wood, though.