If you want to use a stylesheet then your options are going to be limited if you want to keep it all inside sql. SSIS supports xsl transformations via the XML task, although I have rarely used this myself so can't really advise on that http://technet.microsoft.com/en-us/library/ms141055.aspx
SQL CLR is another option if you are able/want to head in that direction.
How complicated is the HTML that you are generating via the stylesheet? As if it is fairly simple, then in theory you could build the html on the fly using t-sql without the need to use a stylesheet.
If you could provide some examples of what the resultant html needs to look like and describe your source table structures then that might help. how is the resultant html going to be consumed?
Personally unless this is only going to be used on an ad-hoc type basic I'd be inclined to move the html generation into an application tier rather than getting sql to generate the HTML itself on a regular basis.