Made the lamp and got it working fine. I suppose it was fine all along but I appreciate the help and support you guys gave me along the way. Thank you all very much!

In lieu of a photograph (for now) I have the schematics http://huncledussey.110mb.com/PL100R_1248.pdf.
The visibly damaged resistor is "R28" which (I am not great at schematics) looks like it lowers the signal for the headphone out (8 ohms). I'm wondering if the 4 ohm speaker was plugged into this when it blew... (I can't recall)
Would you surmise that only the headphone stage is blown?
Should I stick it back in the cab and try it out through the correct speaker out?
I have not touched this thing since it started smoking for fear of screwing something up.
Do you think it would have blown something else up? It doesn't look like anything else is on that path that would effect the normal speaker output. What do you say?

I'm charging up the camera (only 2 mega pixels, so the photos probably won't help much) but I'm looking at the laney head and theres black stuff (dried) coming out of one or the resistors it looks like (R28). R27 is right next to it and looks fine. I don't have access to my multimeter right now so I cannot test them. The last time the amp was in use my bassist was using it to play bass through and black smoke started coming out of the amp. I switched it off and it has not been played through or turned on again.

Preliminarily, does anyone know whats going on here? Has anybody experienced this 'black goo' before? What would the best course of action be? If its a case of replacing the resistor that would be fine, but could it have effected other things as well?

Either way, thank you for helping me. I'll be able to get loud enough now

Is there a section for ss amp repair on here? (I neglected to mention it but the output transistor on the Laney is blown.) I think it is the output transistor, it's two burnt little components on  the pcb right next to the output (need to take a decent picture) not sure if its before or after the effects loop, I think its right before the speaker out though...

Will it use the laney's preamp in addition to the marshall's input, or will the fact that the laney is not receiving any signal from it's input (one of 3!) bypass the laney preamp altogether?

The Marshall has a Line Out, Headphones out and "CD" in. The Laney (dont have it in front of me) has an F/X loop I think. Would Line out to the effects loop work?

http://www.laney.co.uk/manuals/PL50R-65R-100R-100Twin%20Manual%20-%201989%20-%20Issue%201.pdf

I have a solid state Marshall 30w and I want to use it as a pre amp and funnel it into a Laney Pro-Linebacker 100R http://www.laney.co.uk/prod_archive.php. Is there anyway to accomplish such as thing?

The Marshall has a headphone out and a "CD" (aux) input. I'd like to be able to use the Marshall just for tone and push it out through the Laney in all of it's crappy 100 watts of glory. Seriously, I like the gain channel on the Marshall even though its a cheap one.

Am I going to have to build a new output for the Marshall directly after the pre-stage? and then somehow plug it into the power stage of the laney? Has anyone done this? As much as I'd like to buy a new amplifier I really can't and I'd just like to have a louder version of the Marshall anyway, so...

Can anybody help me out on this one? I don't mind having a franken-amp, I just want a loud amp that sound decent.