I assume you need 6+GB of RAM for photoshop or some other heavy image/video editing app. If you want to have a 4-6h battery life, you'd either have to look for a laptop with a mid-ranged GPU or with hybrid power (switching to Intel's GMA HD4500 IGP built into the CPU). Hybrid graphics support tends to raise the price considerably.
First suggestion is Alienware. Dell let you customize it to your needs with a choice of just about every part. Naturally the price escalates too, but you get what you pay for.
Based on a quick internet search, look at some of the high-end Sony VAIO machines like the VPCF11Z1E/BI, or maybe MSI F series (which have that Optimus thing you mentioned that sounds just like hybrid graphics from other manufacturers). The Acer Aspire 8943 may also be worth a look, but it's 18" big and estimated to have a 3h battery life (probably less with the i7 and HD5850 configuration).
Originality always offers awesome advice
That being said, it'll be impossible to find a decent-great gaming/graphics GPU because the GPU is one of the main components that contributes to power drain. Nvidia-Optimus is indeed switchable graphics, and it does tend to raise the price, but it also does raise the battery life. However, I did come up with some options for you as well. Both have hybrid graphics, an i5-i7, upgradable RAM, etc; which does considerably boost the price; depends on what you think you need!
Code:
http://www.xoticpc.com/asus-k42jcb1-p-2752.html
QUOTE said:
* Model: Asus K42JC-B1
* Display: 14" HD LED Glossy (1366x768)
* CPU: Core i5 450M 2.4GHz
* RAM: 4096 MB DDR3 1066MHz
* HDD: 500GB 7200RPM
* CD: Super Multi DVD±R/RW/CDRW
* Wireless: Built In WIFI
Code:
http://www.xoticpc.com/sager-np5125-built-clevo-b5100m-p-2840.html
QUOTE
* Model: Sager NP5125 (Built on Clevo B5100M)
* Display: 15.4" HD+ Glossy (1366x768)
* CPU: Intel® Core i5 450M 2.4GHz
* RAM: 4096 MB DDR3 1066MHz
* HDD: 320GB 7200RPM
* CD: DVD±R/RW
* Wireless: Built In WIFI + Bluetooth