How to get an object charged?
Some thoughts BUT DO read the advice section.


You can use an exiting stream of "stuff" to carry off charge - eg maybe dry air from a compressed air bottle.
You can create charged objects using falling water streams and a small amount of metalwork and very little else.
Friction or charge separation by shearing apart items in close proximity based devices are a staple in this area. Almpst everything works this way. Making them small is mainly a matter of good insulation, cleverness and the breakdown voltage of air or free space.
An electron beam from a number of possible sources may be able to be used. Tends to get high tech.
Ionising radiation sources may be able to be used to convert one sort of energy into another. 




Advice:

You need to specify both your requirements and your limitations and exclusions more tightly.

A Van de Graaff generator will charge an individual object so the sentence "I want to get a particular object charged so Van de Graaff generator is not useful for me" does not make sense as written. You MAY mean that you want to charge an object without needing to have large machinery involved or nearby or ... . What ever you DO want you should say clearly.

You also need to provide more details about the objects and the required voltages and the distances required. These could be two flat 1 m^2 plates separated aqt about Kasimir force distance, or 2 planets in orbit around a start or .... . 

You need to say what the relationship to "ground" is. Can these objects be considered to be in isolation or charged + and - relative to ground or one at ground and the other not and .... . 

In short you need to say a lot more and hide a lot less about your requirement or the question runs a grave risk of being classed as too waffly and getting closed. 
[Not by me - I'm just warning you about what happens.].



ADDED:

The following is all related to particle emission ionisation.
No guarantees as to usefulness. 

Here are a few thoughts and quite a few links.

Electron emission is going to have to deal with air, getting out of the generator and XRays as a byproduct. There is an electron gun in every CRT based TV picture tube. You can make your own (ref below). Electrons fired into a target probably have problems with increasing potential. Electrons fired away from a source towards "infinity" may have less problems if well separated from "ground" or other significantly sized object. 

You could look at using radioactive sources.
This is liable to be a bad idea [tm].
Odds are the rates of production are too low in normally encountered quantities.
Alpha particles are Helium nuclei = 2 protons + 2 neutrons.
Beta particles are electrons.
Thorium is in SOME camping lantern gas mantles emit Alpha particles. Some newer ones use Yttrium which is not radioactive (and not as bright but lasts longer as a mantle)
Various nasty and largely unavailable materials  emit Beta particles - including the Tritium in some luminous materials.



DIY 1800s electron gun - this will kill you if you let it.

http://en.wikipedia.org/wiki/Electron_gun
http://en.wikipedia.org/wiki/Electrostatic_lens
Useful:  https://physics.stackexchange.com/questions/15290/is-an-electron-proton-gun-possible

Useful:  http://books.google.co.nz/books?id=jLAuuBfMr8sC&amp;pg=PA14&amp;lpg=PA14&amp;dq=electrostatic+charging+%22electron+gun%22&amp;source=bl&amp;ots=qwYqsQTniw&amp;sig=o1czASdOFwJhQJ1tXwFv_ke4wHw&amp;hl=en&amp;sa=X&amp;ei=V0TvU-r_E9S78gXHpYCQDw&amp;ved=0CE8Q6AEwBg#v=onepage&amp;q=electrostatic%20charging%20%22electron%20gun%22&amp;f=false

Image search - useful

Electron &amp; ion guns

electrostatic propulsion

Have a look at -ve ion generators

Generating Air Ionization With No Contaminating Particles

[and ion thrusters

and dreamers

These guys seemed to make it work



Jawa with ion gun.

ion sources

Electron guns

Search - Beta emitters

Related:

http://io9.com/5889732/the-thorium-lantern-your-opportunity-for-retail-radiation-exposure

http://en.wikipedia.org/wiki/Alpha_particle

http://en.wikipedia.org/wiki/Beta_particle

Limitation of electrostatic charging of dust particles in a plasma -   (http://onlinelibrary.wiley.com/doi/10.1029/GL011i004p00349/abstract?deniedAccessCustomisedMessage=&amp;userIsAuthenticated=false) - interesting URL :-)

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