Well, it's certainly a good candidate for a mod. Considering how many Mac Pluses there are out there, I would suggest that it won't be missed. Throwing it away is a waste though. List it on eBay and at least attempt to get it to someone for the cost of shipping. You'll likely find a taker with more room to spare.
In therms of resuscitating it, you can probably find a complete logicboard on eBay faster and for less money than a pair of 128K ROMs. However, it sounds like the PSU is in bad shape, so how dedicated are you to the tedious repair work it may require if this is not to be a major machine for you?
If a computer mod doesn't work for you, then you can always make it a practical household item ...
