In terms of taglines, how about
... because your business shouldn't run you

With regards to the name, Here is something for you to consider.

You hit the nail on the head with regards to SEO, taking "virtual" out of your domain name will be a huge ding towards optimization, but it is one that you can make up in your meta tags, header, content, backlinks, etc. - I would be more concerned with excluding the word "Assistant" from your business name. This may or may not be wise choice, depending on what your target customer will be searching for. Are they going to type virtual services into google's search bar? The great thing about SEO is, what you miss in one area, you can make up in another, but of course there is more power in maximum optimization. Domain Name, page headers, content, meta tags, etc. etc. the whole nine.

Just some things to think about. Hope it helps... and best of luck to you