I know that it can be done, just the lamp won't always start reliably. I have heard that shorting the leads to the lamp will create a voltage kick that will start the lamp. Would placing a fluorescent starter in between the leads make the lamp start more reliably?
 

It is done in Europe for certain SON and SOX lamps, although I think a special starter would be needed. You could always try with FS4 starters, but it might not work.

There should be a current limiting resistor in series with the starter (e.g. a 240V/100W incandescent,...), so the current won't exceed the contact rating (~0.6A).

There should be a current limiting resistor in series with the starter (e.g. a 240V/100W incandescent,...), so the current won't exceed the contact rating (~0.6A).

Would this work?
http://www.elightbulbs.com/General-22022-100A19-B22D-220-240V-A19-Light-Bulb

To limit the current, yes.

But if it will reliably start the MH? Not guaranteed, you should try that, it strongly depend on the exact ballast parameters (mainly those normally not that much important, like eddy currents in the core and so on). And it is not 100% sure the starter won't false trigger after the lamp warms up (in the European selfstarting HPS a thermal contact disconnects the starter when the arctube warms up, so the voltage relation between the arc and the starter is then not important).
That are the questions to answer by your experiments... ;-)

Would putting a BBQ grill ignitor start the lamp when pressed? I have seen it done with fluorescent lamps as well as MH lamps on youtube.

I would think it would work. I have done it with a 175w metal halide bulb.

Never tried this--will have to try it-have some 400W PSMH lamps and Probe start MH ballasts of the same wattage.I was under the impression from lamp makers and ballast makers the probe start ballast cannot generate the HV pulse to start the PSMH lamp.I did try a 400W PSMH lamp on a 400W HPS ballast-the MH bulb didn't start.The PSMH lamps need a higher pulse voltage than HPS to start them because of their higher carrier gas pressure in their arc tubes.I was able to run a probe start MH HPS conversion bulb(Venture) from a probe start MH ballast.The Philips Retro-White Master Color CMH bulbs for HPS fixtures won't start from a probe start MH ballast.

I was curious about this too as I have both 175W MH and MV ballasts as well as lamps for both.
Will running a MH lamp on a MV ballast do any harm to the ballast or lamp in the long run ? I have not tried this yet

I heard that it is perfectly fine on both the bulb and ballast, the ballast will actually run cooler.

If the MH lamp works on the MV ballast, it won't harm it but as the lamp wears out it will be harder and harder to start and will eventually fail to start since the OCV of the MV ballast is not high enough for MH.

I'm my experience, 175 will have trouble, while 250+ will be fine, but a bit unstable.

Regarding 250w , i only have 3 MH ballasts and they are rated for both MH/MV no worries there lol
175w MV seems to run perfectly on 175w MH ballasts

175w MV seems to run perfectly on 175w MH ballasts

Yes, there is no problem with that. The older M57 ballasts were rated for H39 as well but new regulations don't permit the dual rating. The ballasts themselves haven't changed and can still run the mercury lamps, it is just a labelling change.

It's the reverse of this situation that can result in problematic starting (MH lamp running on a MV-only ballast).