I dunno. It's doable, just like every build out there. But if you're not going to be in Shadowform that much, why bother putting 31 points into Shadow?
Basically with that build, you're gimping your utility, you're gimping your healing and you're gimping your damage. You kinda need to specialize at 70 to be effective. And blessed recovery is useless. Say you're critted for 1500, healing 25% of that over 6 seconds is 62.5 HPS. If you're going deep in Shadow, you pretty much need to get VT. It is a DoT that scales incredibly well with gear and gives back mana. A build like the one you posted, what's it getting you? You still won't be able to heal raids, you'll have less mana efficiency than a full disc or full SP, and you won't be returning mana to your party.
If you are trying to make a PvP build, (I think you are?) maybe try something like this. http://www.wowhead.com/?talent=bxGMzhMZbZVMGdMuRhtio That's pretty much the build I use. It has great utility in that, while you are still putting out mad DPS, you can pop out of SF and effectively heal. You also have Imp. MB, which is an incredibly undervalued spell.
Edited, Dec 16th 2007 10:51am by Schmere