here is a simple mod - rocket flame light dome
not the cheapest option from shape ways, but that is due to the resin printing process
https://www.shapeways.com/product/6ZEQ66VSC/party-zone-pinball-rocket-flame-light-dome?li=search-results-1&optionId=57755057Alternatively I can print one for $25 posted anywhere in Aus from my printer and have semi-transparent PLA and it looks real nice. Simply swap it out with your regular light dome for the flame dome and put in a coloured led (red, orange or yellow) or use some glass paint (on the inside or outside) to achieve a cool flame effect.
The inside is hollowed out with a tapered starburst effect to aid in spreading the light and each outer side is different with a random flame effect.