What about doing that? Keeping it simple. Using colored BC...just ice some candles on the 9x13 cake. That way...it's easy for you, but colorful and something she likes. I sketched up a picture of what I'm talking about. I'll attach it. You could even make different designs on the candles but that might be too busy. Or, just use a different tip to ice each one...that way they each have a different texture. If you could get your hands on some gold or yellow luster dust, I would blow that over the top half of your cake before you do the candles...then it would look like the glow of the candlelight. Just an idea. I hope if it doesn't work for you that it atleast sparks something!
Good luck!
How about something like this ...I found it in the gallery under candles.. made by sweets2eats...I LOVE THIS DESIGN!
http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=2110
OMG, that cake made by sweets2eats is soo creative and cute! That would be perfect for a house warming party...... now who do I know that is moving.... 
Ok, here is the final cake. I finished friday am before work and took the pic to her to see. I don't know if she liked it or not. I got that feeling b/c of little comments she made. After work she said she would call me that night to come pick it up. WELL, finally at 9:15pm she called and said she would come get it in the am. Then when she came and picked it up she said it was so pretty. Who knows what she really thought. Maybe she will tell me how it went at the party. She got EXACTLY what I told her it was going to be (for a steal) Oh well, DH said the cake scraps were AWESOME and if she didn't pick up the cake he would be happy to get rid of it... 
Make a cupcake or two and decorate them like a candle and set them on top of the cake.
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