I have a well-insulated little Bradley smoker with a heating element that holds the temperatures really well in the range typically used for bows.
It makes me think that a similar setup would be far better than using lightbulbs in heat box: more compact, more durable, more efficient. Insights from folks who have tried this would be very much appreciated.
It seems likely that one would need to shield the source and circulate air with a fan to heat evenly, but those should be simple enough issues to overcome if one had a suitable heating element.