SFX has a wonderful interview with Simon Clark, regarding a sequel to Paul Cornell's "Scream of the Shalka". Clark, a respected SF/horror writer (he'd done an authorised sequel to "The Day of the Triffids", as well as his own novels), was working on a Telos DW novella at the time, and was asked to provide a script for a followup webcast. He was halfway through the writing of "Blood of the Robots" when the news came through about RTD's new telly project, which squashed the whole concept. Details at the link, but apparently Clark's story would have involved "a world full of intelligent, sensitive robots that have been abandoned by their human owners, who are too squeamish to ‘kill’ them when they’re obsolete. Now ruthless salvage squads are hunting the robots in order to make room for human settlers forced to migrate from their dangerously over-crowded home planet".
"Shalka" was, of course, meant as a proper continuation for DW, with a new Ninth Doctor and all (we'd link you to the relevant BBC DW website, but strangely enough the Wayback Machine capture for July 2003 doesn't work). SFX missed a trick by not linking to Richard E. Grant's website archives, which include their own news article about Shalka from that summer and provides more details about the planned series. Including a suggestion that they would have dealt with the McGann regeneration, in good time. James Goss, the BBC Cult webmaster at the time and producer of "Shalka", had been quietly building up website content and animated projects to get to the point where they could be talking about restarting Doctor Who with a webcast series (there's a tantalizing snippet about a BBC internal meeting on the webcasts here). In a recent Kasterborous interview, Cornell mentioned the Clark story and indicated that he'd been working on the overall storyline of the series, as you'd expect him to do. It sounds like it might have been able to tie in with the BBC Books EDAs, actually: "Gallifrey had been destroyed; the planet was still there
but all the Time Lords were in the Matrix. And I think the Master had
been downloaded into the robot."
A blogger who was at the Aaronovitch-Cornell urban fantasy talk at the Edinburgh Festival has yet more info on the planned webcast series; James Swallow was to write a story named "Memoria" that would focus on the Master (he hadn't written for DW at that point, but has since done a spin-off novel and several Big Finish scripts). Stephen Baxter, another big name in the British SF community, was working on a story called "The Forest of Ancestors" that would have dealt with "a race of people who were living trees" (since then, he's done a Troughton novel called "The Wheel of Ice"). Given that Big Finish are wrapping up the Lost Stories and suchlike, one wonders whether they'd be interested in resurrecting these might-have-been stories...