Here's a few:
MastSend
ShadowSend
PrivateSend
PrivacyTX
EnhancedPrivacy
UltraPrivacy
There is already darksend, cloaksend, libertysend, supersend... so i don't think MastSend would be good
MastAnon, MastGuard, SafeSend, PrivateSend.
One little advice, try to keep activity on twitter, it does not inspire confidence to see there is no new tweet for almost 1 week.
That's exactly why MastSend is an option. Keeping the same nomenclature for like-functionality in products can be useful as it instantly helps your audience identify what you're offering. Having a unique name also has its benefits though, of course. "MastSend" isn't our top pick, but whether it is the best name or not is what's up for discussion

Our team's favorite of the names we listed and have seen discussed so far is probably PrivateSend, as it seems to best convey the idea we're trying to community. "MastCoin, now with PrivateSend(tm) technology!" sounds pretty good initially. But, we would love to see more brainstorming and suggestions from the community!
We're going to work on ramping up our Twitter activity. We can also consider scheduling tweets, if anyone here wants to take the lead on helping write up a bunch of tweets to schedule.