MOTM

does anyone know of an low frequency oscillator design that would give 
me an output similar to what is in the graph below?

http://www.etanstudios.com/images/dualoutoscgraph.gif

i've been working on this project for months now and i'm ready to rip my 
hair out. here's the scenario, i have two slide projectors, i've built 
dimmers for both lamps that accept a DC control voltage of up to 10VDC. 
what i want the projectors to do is similar to what a dissolve unit 
does, but at a variable rate of speed (0.1 Hz to 10Hz triangle wave) the 
voltage of output number one needs to start high and drop to zero, at 
the same time output 2 needs to start at zero and end up high in sync 
with output 1 going to zero. (the chart explains it better than i can) i 
cannot for the life of me figure out how to keep the entire triangle 
wave in the positive realm, nor have i been able to figure out an 
inverter to get output 2. i'm not that bright when it comes to 
electrical design, so any help would be appreciated... hell, i'll even 
pay someone (within reason) to draw up a schematic for me. if anyone has 
any insight into this, please email me privately so we don't piss off 
paul. and this is slightly synth related as we use this projection 
system during our shows, in which i am using the MOTM system (yeah, I 
know, that doesn't cut it...) thanks to everyone in advance for your 
help and tolerance. -nate