Well here's what i understood from your question:

1- If you are using as a domain name, the similar variation, then there is nothing to worry about. However, if you are gonna Title the page according to the other company's domain name, then you got the following...

2- If their domain name is also the name of their company, there might be issues. For that you will need to check the trademark laws and details.

3- On the other hand, if it is only the other company's domain name, and in your website you are using it without the suffix (.com) then there should be no issues whatsoever.

The most important issue usually is, would the name you want to use confuse visitors into thinking you are affiliated to the other company??
My advice would be to manage the design in such a way that the name would be seen simply as a title you are giving yourself rather than the actual name of your "shop" or "business".

For most definitive answers if you still have your reservations, Godaddy has alot of answers, and are pretty good with customer support... at least I never had any issues from that point, and i call them internationally....

Hope this helps!
Marc