Well its not entirely new but give a unique twist on rss submitting. Go to: http://www.rssmix.com and use the form to create new rss url from combination of rss from your sites. Rssmix will create a new rss feed for you. You can mix your site rss feed in the same niche and create whole new address rss with it and then submit them to rss aggregator. Simple but pretty powerful.
I saw this on a video somewhere that said to mix lots of your rss feeds from social bookmarking sites and then submit these to directories for backlinks never tried though
That would be a good idea too, I got lots off backlinks from rss aggregator like feedage.com and feedrider.com by submitting my feeds to them.
that's an excellent video and well worth watching, the girl knows her stuff... http://www.buzzblogger.com/videos/instant-backlinks/
Great tip Also makesure you have anchor text backlinks in the snippet copy of your RSS feed. . . . This gives the technique above even more link power.