Manicart - I don't think you necessarily need to have a script, just send in 4 or 5 pages of artwork, making sure that your art tells a story over those pages. Send in relevant characters, i.e. don't send Spider Man artwork to Tharg, send Dredd artwork. Go to Comic Conventions with your portfolio; pester the editors; don't give up.
You said in your post that approaching 2000AD you'd be unlikely to get any response, well, one thing's for sure, if you don't try you'll never know. Go for it, nothing ventured, nothing gained!! You don't even have to go the small press route. If you've got the cheek, perseverance, bottle, and, of course, some skill, you'll be surprised what can happen.
Oh! nearly forgot, the thing that budding artists tend to forget are deadlines. It's a completely different ballgame knocking out some beautiful art in your spare time when you can take as long as you like than it is meeting deadlines for the editors. You have to be disciplined and sometimes you have to forgo perfection to meet those same deadlines. In your submissions it may be a good idea to inform the editors how long it takes you to produce a page of work, i.e a page of pencils, a page of pencils & inks, a page of pencils, inks & colours. And it's very important not to "fib" over this last point, you'll soon get found out!!!
Hope this may help.
