Are there DNS servers supporting ALIAS type for apex records?

DNSimple and AWS Route53 are supporting ALIAS records that allow similar functionality to CNAMES for @ (Apex) records in DNS.

I'm running a DNS server (Bind) that is currently hosting around 1500 zones. Most of the zones have @ record configured to the same IP-address. In order to achieve the same flexibility provided by CNAME records i want to do the same with @ records and provide this to my customers.

It seems that DNSimple has built a custom solution for this. My question is that is there any DNS server software that support this? Would it be an option to write extension or plugin for Bind that allows this?

If you want to run you own DNS Server, you can have a look at PowerDNS on Git.

https://github.com/PowerDNS/pdns/tree/alias

You need to build it yourself but in the "alias" Branch is their current implementation of ALIASRR and it works fine.

No, because it's just that -- a custom solution with no basis in any DNS RFC.

http://support.dnsimple.com/articles/differences-between-a-cname-alias-url/

Before going further into the details, it’s important to know that A and CNAME records are standard DNS records, whilst ALIAS and URL records are custom DNS records provided by DNSimple. Both of them are translated internally into A records to ensure compatibility with the DNS protocol.

While someone may put together some form of plugin for them, do not count on this happening. Without a RFC describing the behaviors that the servers must adhere to, the amount of professional interest in doing such a thing will remain extremely low. As it should.

That said, if you have a need to bulk define a number of identically configured domains, there's nothing stopping you from defining a single zone file and using it for multiple zones.

I was looking at that dnsimple article and seeing what I could find on the subject. So far it appears that this is a growing DNS use. An increasing number of providers are implementing the DNAME record which is specified in RFC 2672: Non-Terminal DNS Name Redirection

DNSimple are offering a slightly custom solution, although this may in fact be a translation layer to make things easier for their users.

Dynect are offering this as part of their Managed DNS service

AWS Route 53 is supporting the redirection of Apex domains which allows them to support using S3 / Elastic Load Balancer / CloudFront. They have guidance on this in their documentation. Search aliasRR for their docs.

As @bitcloud stated in his answer, PowerDNS supports "virtual" alias records. In addition to compiling the software yourself, you can simply install it from your system's official repositories. If you use Debian or Ubuntu, installing it can be as simple as:

apt install pdns-server pdns-backend-bind

I included the bind backend package because I assume many will want to reuse their existing zone files. Install a different backend if you need something else.

More info about PowerDNS installation and configuration is available here.