If I can jump in here a little, Henrik, reading this post back it is clear that you have done a lot of work, a really lot of work.
I do not have a one of the shields but I have been learning with one of the wiznet modules. My interest got started based on the thought that just about every fricken thing out there (machines and controllers etc) wants to be able to hook up to the internet, somehow or other. Many things are already doing that more and more, but its still interesting understanding how that all works.
So, at this point, I have a PIC recieve a request from HTTP and send 1 page , as you have done over IP.
Name: Capture13.JPG Views: 2054 Size: 117.9 KB
Not sure what to elaberate on, so when brought up,
1- Use word pad to write and test HTML, very easy
2- Jscript & Jquery to make pages more active
3- Save HTML at end of code with 'db'

Code:
 ''==============TABLES============= ''!!! ADD 0,0,0 TO END  
ASM                                            
tbl1   org 0xA400  
        db "HTTP/1.0 200 OK",13,"Content-Length: 800 ",13,13
        db "<html>",13,"<h1> PIC 18F...TT Server v1.0</h1>",13,"<input type=",34,"text",34," id=",34,"txt",34,">"
        db "<script type=",34,"text/javascript",34,">" ,13," var c=0;var t;var timer_is_on=0; "
        db "function timedCount(){document.getElementById('txt').value=c;c=c+1; "
        db "t=setTimeout(",34,"timedCount()",34,",1000);}function doTimer(){if (!timer_is_on){timer_is_on=1;timedCount();}} "
        db "</script><form method=",34,"get",34,">Project name: <input type=",34,"text",34," name=",34,"PIC",34," value=",34,"PIC18F2525 ",34," />"
        db "<br>select one: <select><option>Amps</option> "
        db "<option>Volts</option><option>Frequency</option> </select>"
        db "<input type=",34,"submit",34," value=",34,"Submit",34," /></form> "
        db "<body onLoad=",34,"doTimer()",34,"><p><b>Note: TEXT HERE </b><br><script type=",34,"text/vbscript",34,">"
        db "document.write(NOW & ",34," Hello World!",34,")</script><br></body></p> </html> "
        db "<style type=",34,"text/css",34,">body{background-color:#d0e4fe;}h1{color:red;} style> "  
        db "<BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR> ",0,0,0
        db "<BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR> ",0,0,0
ENDASM
'''---------------------------------------------------------------
(format of code window?????)
4-Wiznet, use PC interface prog to set IP, port ,Server, or client mode, unloads PIC of teedious work
5- DHCP not so good if device is server because IP needs to stay static so can be found from outside more easily.
6- Idea to store a main HTML page on ones local computer (can have been tested and downloaded) and just have PIC send the dynamic data, and thats Jscript
and------ Someone can make a formater so HTML ,created and tested with any text prog can be inserted into 'db' asm code with correct punctuation, legnth etc. The "" quotes do not get handled properly.
7- mabye load new pages into flash somehow, without reprog of PIC.
thats enough for now.
Happy to give and get knowledge.
Don