is in attendance any laptop of 4 gb bump?

Answer:

Dell have a few laptops that can have 4GB of memory, but you involve to make sure you enjoy a 64-bit OS AND a 64-Bit Processor or the OS will not be able to use adjectives 4GB. Depending on what you want to do, it may be better to settle for 2-3 GB of RAM.
Yes.
I Think Alienware
Yes, Dell also sells a 4GB hit laptop.
Generally, most companies don't have 4 GB of hit pre-installed in the operate. I've seen up to 2 GB max usually. Why not a moment ago upgrade to more RAM later on? Laptops usually own room for more RAM upgrades. Just make sure you check to see if the specs speak the laptop can support up to 4 GB, which many do, such as the XPS systems from Dell.