Joe, No, there isn't any substitute for the accented letters except using slashes, which makes the writing awkward to read and also banjaxes the searches. Once upon a time dots where placed on top of letters to indicate lenition, but in modern type the dots are indicated by the letter 'h' (as in 'an Mhaighdean Mhara'), so at least we don't have to dot our b's, c's, d's, f's, etc. I can usually understand Gaelic written without accent marks - distinguishing between words like 'cead', 'permission' and 'c‚ad', 100, by the context; but it's not nearly as easy to read and I might mispronounce a word or two. Also I have seen some serious mistranslations occasioned by learners using a dictionary to translate a word which doesn't have the correct accents or has them in the wrong place and therefore becomes a different word.
I correspond in Irish with someone whose outmoded computer can't read the diacritical marks in e-mail messages. If I'm sending her a copy of something written for other readers, I don't go to the trouble of taking out the accents, but I do type in a decoder. So I type ¢ = o/ , but Julie sees = = o/ , etc. But she's quite fluent in Irish and also quite used to the strange spellings she sees on her screen.
I said I'd need 10 HMTL commands, but it's 20 if I bother accenting the few capital letters! Does George Seto's simpler method work?