I don't think there's such a dictionary that will work with Pleco, but I purchased an electronic dictionary in China made by a company called Noah which had specialized dictionaries for technology terms, business terms, etc..
It was complete crap compared to Pleco, and seemed to be written by a team of engineers their first year out of school, but it did give me access to obscure words I couldn't find in Pleco's dictionaries. (After using a Chinese-made dictionary, you'll really appreciate the ease-of-use of Plecodict so much more!) The dictionaries were excellent in terms of completeness, but intended for Chinese students, so their Chinese explanations for terms were better than the corresponding English.
So if you're located in China, you may try one of the local electronics stores. If you can read Chinese, take a look at their web site at
http://www.noahtech.com.cn
A Noah with handwriting recognition might set you back 900-1100RMB in China.
This web page compares dictionaries and recommends alternatives to Noah
http://www.chinese-forums.com/showthread.php?t=24057
Finally, if you want an English explanation of Chinese-made dictionaries, visit the expat web site at
http://www.expatmart.com/category.php?id=1137
(I didn't find their English product descriptions all that helpful, but it's better than nothing.)
Hope this helps!