Is it possible to create custom bar types in jforex? Or is this being considered for future versions?

There are several other platforms that can do this and it is one of the only things that I'm missing from jForex.

See:
https://www.dukascopy.com/wiki/#Chart_feeds

I'm already familiar with the types of bar aggregations you already support.

To be more clear, I want to create my own custom bar aggregator function that accepts tick data and generates bars.

For example, I would like to create a dynamic range bar that changes it's 'size' based on volatility of recent ticks. I'm fairly certain you don't allow custom aggregations now, but would you consider this as a feature in the future?

I've found that custom bar types can be extremely helpful in reducing noise and tracking current market conditions without having to build 'adaptive' indicators.

NinjaTrader has this capability.

In your strategy you can aggregate the ticks however you want, see, for example:
https://www.dukascopy.com/wiki/#Custom_renko_aggregation
Another option is to make an indicator like, for instance, Heikin ashi, which creates its own candles.
Please make your feature requests in Automated Trading -> Feature Requests. In this forum section we only advise on the current JForex-API functionality.