From Steve’s post on the mental ray and iray thread on the mental images forum it seems like other lights should work as well:
Common Light Sources (ambient, directional, point, spot)
[ul]
[li]Maya light sources with high intensity values[/li][li]Maya light sources with custom light shader physical_light[/li][/ul]
Area (Shape) Lights
[ul]
[li]Maya Area Light with mental ray Use Light Shape enabled, all shapes supported except user[/li][/ul]
Environment Lighting
[ul]
[li]use Maya camera Environment / Background Color[/li][li]use environment shader on Maya camera mental ray Environment slot[/li][li]for IBL from HDR image, use mib_lookup_sperical[/li][li]for Sky Light, use mia_physicalsky[/li][/ul]
Light Emitting Objects
[ul]
[li]mia_material_x with additional color on any shape[/li][li]mia_light_surface on any shape[/li][/ul]
However, I’m curious if the portal light is supposed to work with iray in 2012. Can anyone confirm or deny this? I tried to get it working last night but got horrible results. But in all honesty my horrible results could be because at this point in time i have no clue what the hell i’m doing with iray. 