I also had a Wordtank V80 for about a week before a chubby friend stomped it out of existence... additionally, that was a long time ago and I didn't know much Japanese at the time so I can't even say if I thought it was good or not or if there is a nice solution to your problem.
For the past few years I've held on to a little Sharp PW-M800. It's so-so, does all I need. As far as the kanji lookup goes, it offers four lookup methods that can be combined for faster searches: 部品読み、音訓、部首面数、総面数 . I think you were referring to the 部品読み where you can enter the readings for the different parts, like you could write みず and き and a little searching to find 様 in the list. But searching by any of those individual terms will not be so effective, combining them produces quick efficient searches that I can't complain about; I think that is the standard kanji lookup method for most dictionaries.
Additionally, and I also think this is standard, you can highlight any kanji and jump to its kanji page. On the kanji page, there is a tab that lists the combinations of that kanji that appear in the 広辞苑 (does yours have 広辞苑 or possibly 三省堂？) and so you can jump that way. Like you see 参照 but you can't remember the reading, but you know 参考 so you punch that in, jump on the 参, and then scan the list of combinations for 参照. Again probably pretty standard.
For everyone using the software and palmpilot based systems, and anyone thinking it would be easier with direct pen input, I can assure that while these methods may seem tricky at first and they definitely require some up-front kanji knowledge, the result is much faster and easier to use kanji search.
And for the record, my 電子辞書 is light-weight and everything and good long battery life, but maybe the wordtank is better. Really, though, in the end I think getting the cheapest of the real ones is the best bet; anything with either the 広辞苑 or the 三省堂 and provides a kanji search feature is all any lower-intermediate to upper-advanced Japanese language learner needs, so just go cheap and you're fine. For those times that you need to look up more advanced words, use the eijiro at http://www.alc.co.jp/index.html
Hope that helps,
For the past few years I've held on to a little Sharp PW-M800. It's so-so, does all I need. As far as the kanji lookup goes, it offers four lookup methods that can be combined for faster searches: 部品読み、音訓、部首面数、総面数 . I think you were referring to the 部品読み where you can enter the readings for the different parts, like you could write みず and き and a little searching to find 様 in the list. But searching by any of those individual terms will not be so effective, combining them produces quick efficient searches that I can't complain about; I think that is the standard kanji lookup method for most dictionaries.
Additionally, and I also think this is standard, you can highlight any kanji and jump to its kanji page. On the kanji page, there is a tab that lists the combinations of that kanji that appear in the 広辞苑 (does yours have 広辞苑 or possibly 三省堂？) and so you can jump that way. Like you see 参照 but you can't remember the reading, but you know 参考 so you punch that in, jump on the 参, and then scan the list of combinations for 参照. Again probably pretty standard.
For everyone using the software and palmpilot based systems, and anyone thinking it would be easier with direct pen input, I can assure that while these methods may seem tricky at first and they definitely require some up-front kanji knowledge, the result is much faster and easier to use kanji search.
And for the record, my 電子辞書 is light-weight and everything and good long battery life, but maybe the wordtank is better. Really, though, in the end I think getting the cheapest of the real ones is the best bet; anything with either the 広辞苑 or the 三省堂 and provides a kanji search feature is all any lower-intermediate to upper-advanced Japanese language learner needs, so just go cheap and you're fine. For those times that you need to look up more advanced words, use the eijiro at http://www.alc.co.jp/index.html
Hope that helps,