David Scotson

Here's an interesting resource with advice on using transitional XHTML, CSS and table-based designs from some of the people behind the NYPL site mentioned earlier.

http://www.zeldman.com/dwws/

The two sample chapters are well worth reading and I would recommend buying the book to anyone interested in web design.

With regard to using a different template, I don't think the differences warrant the effort of diverging from the majority. Creating a valid (X)HTML + CSS webpage layout that works as expected across a wide range of browsers/screen sizes/devices/people while conforming to accessability standards is tricky enough without splitting your potential developers/users across two competing layouts.

I think the key to the answer is that there is a step between HTML 4 tag-soup and XHTML. Using one of the HTML 4.01 doctypes would give all the benefits of using one of the XHTML 1.0 doctypes, such as being able to validate the output for correctness and working correctly with CSS stylesheets, without any of the drawbacks.

It would also provide an convenient stepping stone if you intend to transition to XHTML gently rather than all at once.
You could, perhaps, move the current HTML into templates as-is, to make for a less daunting initial milestone. This would allow easy access to the parts most in need of a clean-up and you could then set validation, greater use of CSS, and any possible move to XHTML as longer term goals that can be approached on a page-by-page basis and are decoupled from the PHP development and each other (to a degree).

This is probably the best summary of the pro's and con's though it does get quite technical in places.

http://www.hixie.ch/advocacy/xhtml

I'm intrigued by your comment: "XHTML compliance is a must."

I have read widely on this topic and found the implications convoluted, to say the least, and that there is certainly no wide community consensus on the issue.

In fact the benefits/costs on both sides seem quite minimal and real-world factors appear to render this point moot for many people.

I could dig up some links on the subject if anyone is interested.

Tying this to the XSLT/smarty discussion, given the stated aim of decoupling presentation, did you perhaps mean that *potential* XHTML compliance is a must."

(for info: I work alongside Howard Miller, the originator of this thread)

I read the linked post and it reminded me of a question I had for you:

It appears to me that smarty templating was being mooted as a rival technology to XSLT and a choice had to be made between the two.

If this is the case then my question is what would be used to generate the XML that is then transformed via XSLT into the final (X)HTML output?

The best answer seems to be smarty!

Is this what you mean when you say it is still on the agenda?