Sorry to drag up this again, but you might find this of interest. Short S.36 Stirling III, or 'Super Stirling', a little info from British Secret Projects, Fighters and Bombers 1935 - 1950 by Tony Butttttler:
The S.36 had redesigned wings and a longer fuselage which featured a large central bomb bay for various loads, including one 8,000 lb weapon; this represented a big improvement over the Stirling's individual bomb cells, while six more wing cells could each take a 1,000 lb bomb. There were also changes to the empennage but a large proportion of the 'bits and pieces' used in the fuselage were retained. CRD described the new type as 'a typical night bomber having high useful load at a comparatively slow, economical cruising speed' (214 mph) at 15,000 ft, just 6 mph more than the Stirling, but he recommended that a production order be placed. The S.26 had a defensive armament of two .50 in machine guns in the nose, four more in both mid upper and tail turrets plus an under turret with two .303 in machine guns. It was not seen as an all new type, but shared a 'general similarity' to the Stirling.
The first estimates were completed on 15 July 1941 and gave an all up weight of 103,000 lbs and at 80,000 lb weight a top speed of 311 mph at 20,000 ft and service ceiling 29,300 ft. A month later Liptrot revised this to 105,000 lbs and 295 mph at 20,000 ft against 70,000 lb and 282 mph at 12,500 ft for the Stirling, but he considered the project 'to be well conceived and to be a logical next stage in the development of the heavy bomber.' The project was seen to have a similar take-off and flight performance to the Stirling but with much increased bomb load/range characteristics. Over 1,000 miles the S.36 could carry 23,500 lb of bombs against the Stirling's 14,000 lbs for 2,300 miles range it could take 10,000 lbs against 4,500 lbs.
On 19 November Specification B.8/41 was raised to cover the project, but from the point of view of heavy bomber production some within the Air Ministry were apprehensive about introducing the new type. The Controller General stated that the present Stirling is not designed for larger scale production as efficiently as the Halifax or Lancaster and it would be better to ask Handley Page or Avro to design a super bomber.