Wow, Heim theory! I haven't seen that mentioned in a long time.
I think I remember reading that supposedly someone was going to try to test it. I'll have to dig around and see if anyone found anything worthwhile. A long shot, of course.
Last time I saw it discussed was the aftermath of an ESA experiment that created artificial gravity many orders of magnitude greater than relativity says should have been produced. It was mentioned as a thereotical framework that might account for it.
http://en.wikipedia.org/wiki/Artificial ... omagnetism
http://en.wikipedia.org/wiki/Heim_theor ... vity_force
Heim's predictions for a quantum gravity force
In the 1950s, Heim had predicted what he termed a 'contrabary' effect whereby photons, under the influence of a strong magnetic field in a certain configuration, could be transformed into 'gravito-photons', which would provide an artificial gravity force. This idea caused great interest at the time . A recent series of experiments by Martin Tajmar et al., partly funded by ESA, may have produced the first evidence of artificial gravity  (about 23 orders of magnitude greater than what General Relativity predicts). As of late 2006, groups at Berkeley and elsewhere were attempting to reproduce this effect. By applying their 'gravito-photon' theory to bosons, Droscher and Hauser were able to predict the size and direction of the effect . A further prediction of Heim-Droscher theory shows how a different arrangement of the experiment by Tajmar et al. could produce a vertical force against the direction of the Earth's gravity. However, in July 2007, a group in Canterbury, New Zealand, said that they failed to reproduce Tajmar et al's effect, concluding that, based on the accuracy of the experiment, any such effect, if it exists, must be 21 times smaller than that predicted by the theory proposed by Tajmar in 2006. Tajmar et al., however, interpreted a trend in the Canterbury data of the order expected, though almost hidden by noise. They also reported on their own improved laser gyro measurements of the effect, but this time found 'parity breaking' in that only for clockwise spin did they note an effect, whilst for the Canterbury group there was only an anti-clockwise effect . In the same paper, the Heim-Theory explanation of the effect is, for the first time, cited as a possible cause of the artificial gravity.
More testing needed, I guess. I briefly corresponded with Tajmar at the time; I'll have to ask if anything new is forthcoming.